1. Field of the Invention
The present invention relates to the field of graphics, and more particularly, to the use of dependency graphs for the control and management of the graphics creation process.
2. Related Art
Conventional graphics systems have a plurality of subsystems. These subsystems include, for example, animation, construction history, deformation, and most recently user defined functions. These subsystems, however, all compete for control of certain data and each subsystem is rigidly defined by the structure of the software. FIG. 2 illustrates five subsystems, each of which is connected to communicate with the others. The main drawback of these systems is that they all required complete knowledge of each other in order to operate. As additional subsystems (functions) are added to the system additional connections have to be added. A further problem is that users are never sure how a particular function will react with other functions. As a result, programmers were forced to write code that had to interact with the growing number of subsystems and their own particular quirks. Yet another problem was that the sequential order in which the subsystems executed was rigidly defined by the software.
A prior solution to this problem concentrated solely on the transfer of data. For example, the dataflow method of control has been used for many years in the scientific visualization and image processing domain. However, a more flexible structure is to allow the transfer of information as well (e.g., algorithms or actions).
Thus what is needed is a method of controlling a graphics processing system which includes a plurality of unrelated operations in which information, and not just data, can be transferred between the operations.